J-56 CALIPERS

[�RJAN JOHANSSON]

I have a Corvette-67 427/390Hp whith J-56 HD brakes, my problem is they have change the J-56 calipers to regular calipers. I try to find a set CORRECT J-56 calipers but i dont have the casting numbers.
Is there casting dates on calipers?
Is there anyone how can help me?

[Joe L.]

Re: J-56 CALIPERS

Orjan----

Very early 1967 Corvettes used the "1st design" 65-66 style calipers. For these, the only difference between standard and J-56 was the front caliper pad retention system. Standard used single pin and J-56 used dual pin. Otherwise, the calipers, including all internal parts, were the same as standard. Both standard and J-56 used the same insulated pistons with integral piston guide pins on the rear and the calipers had cast-in piston guides. These calipers were the same casting numbers as standard brakes and all caliper half casting numbers will begin with the number "546".

Most 1967 Corvettes used the "2nd design" calipers. Once again, as far as the calipers themselves go, the castings were exactly the same as the standard brake calipers. The only difference was that the front calipers for standard brakes used the single pin pad retention and the J-56 used dual pin. To manufacture these, Delco-Moraine used the same caliper castings. For J-56, the central single pin bosses were machined off and the 1/8" holes for the end-mounted dual pins were added. A J-56 caliper can be similarly created today from a standard caliper. VERY easy to do. The caliper casting numbers were exactly the same for standard and J-56. For 1967 "2nd design" J-56 all of the caliper casting numbers will begin with "545".

The internal parts of the "2nd design" calipers were different, though, for standard and J-56. The differences involve the pistons. For all "2nd design" pistons there were NO piston guides on the pistons or in the caliper bores. The standard calipers used non-insulated pistons. The J-56 used insulated pistons. However, the insulators were much thicker than those used on all "1st design" pistons.

While "2nd design" J-56 calipers can be easily made from standard calipers, obtaining the pistons is MUCH more difficult. The "2nd design" J-56 pistons and insulators are long-since discontinued and not reproduced. Since the piston, themselves, are very susceptible to wear and deterioration, used ones, even if you find them, will likley not be serviceable. The insulators can be re-used but without serviceable pistons upon which to install them, they won't do you any good.

There are no meaningful dates on caliper castings of either the 1st or 2nd design. If there are any dates, at all, they don't include a reference to a year so they are rendered essentially moot.